{"id":11829,"date":"2021-03-01T20:49:20","date_gmt":"2021-03-01T12:49:20","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/component-fatigue-caused-early-shutdown-of-merlin-engine-on-last-spacex-launch\/"},"modified":"2021-03-01T20:49:20","modified_gmt":"2021-03-01T12:49:20","slug":"component-fatigue-caused-early-shutdown-of-merlin-engine-on-last-spacex-launch","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/component-fatigue-caused-early-shutdown-of-merlin-engine-on-last-spacex-launch\/","title":{"rendered":"Component fatigue caused early shutdown of Merlin engine on last SpaceX launch"},"content":{"rendered":"
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File photo of nine Merlin 1D engines firing on a Falcon 9 launch in 2018. Credit: SpaceX<\/figcaption><\/figure>\n

SpaceX has concluded fatigue on an engine cover caused one of the nine Merlin 1D first stage engines on the company\u2019s most recent launch to shut down early during ascent, leading to the loss of the booster during an offshore landing attempt in the Atlantic Ocean, an official said Monday.<\/p>\n

A hole developed in one of the covers on the Feb. 15 launch, allowing hot gas into one of the engines, according to Benji Reed, senior director of human spaceflight programs at SpaceX. Reed disclosed the findings in a press conference Monday previewing SpaceX\u2019s next crew launch for NASA, currently scheduled to fly to the International Space Station in late April.<\/p>\n

The early engine shutdown did not affect the Falcon 9 rocket\u2019s primary mission, and the launcher\u2019s upper stage continued into orbit and successfully deployed 60 Starlink internet satellites about an hour after the Feb. 15 liftoff from Cape Canaveral Space Force Station. But the problem prevented the rocket from landing on SpaceX\u2019s floating drone ship positioned around 400 miles (630 kilometers) northeast of Florida\u2019s Space Coast.<\/p>\n

Reed said the Merlin engines fly with covers, or boots, to protect certain components during flight. One of the boots on the Feb. 15 launch, which flew with a reusable first stage making its sixth trip to space, had more flights than any other boots of the same design, Reed said.<\/p>\n

\u201cThis particular boot, had a little bit of a hole,\u201d Reed said. \u201cIt developed a hole. There are hot gases. Of course, that\u2019s what makes the rocket go up, very hot gases coming out of the engine. But you want those hot gases to be where they\u2019re supposed to be and not go where they\u2019re not supposed to be. So that boot, a little bit of a hole developed, a little bit of hot gas got to where it\u2019s not supposed to be, and it caused that engine to shut down.\u201d<\/p>\n

The Falcon 9 rocket has nine Merlin 1D engines, each consuming a mix of super-chilled, densified kerosene and liquid oxygen propellants. The nine Merlin 1D engines collectively generate about 1.7 million pounds of thrust at full power. A single modified Merlin engine flies on each Falcon 9 upper stage.<\/p>\n

With a cluster of first stage engines, the Falcon 9 is designed to overcome an in-flight engine failure and still deliver its payload into orbit.<\/p>\n

\u201cThat\u2019s the great thing about Falcon 9,\u201d Reed said. \u201cWe have engine-out capability, plus this vehicle has all of these great systems to autonomously control itself, shut down, abort when it needs to. In this case, it did exactly what it was supposed to do, it cut out that engine, turned that engine off. The vehicle was safe. The vehicle got to orbit, put the satellites exactly where they wanted to be, the primary mission was accomplished.<\/p>\n

\u201cWhen that booster came to return home, because of the problem with that particular engine, we didn\u2019t have enough thrust in order to get back to where we needed to be,\u201d Reed said.<\/p>\n

SpaceX did not disclose the ascent engine shutdown until Monday. The engine problem on the Feb. 15 launch was the third time a Merlin booster engine has shut down early on a Falcon 9 launch.<\/p>\n

A Merlin engine on an earlier Falcon 9 variant failed in flight in 2012, but the rocket continued into orbit and deployed a Dragon cargo ship on a mission to the International Space Station. But the upper stage\u2019s firing to overcome the first stage engine failure left insufficient fuel on-board to maneuver into a separate orbit and release an Orbcomm communications satellite.<\/p>\n

A Falcon 9 launch in March 2020 also suffered an in-flight engine failure, producing a similar outcome to the Feb. 15 mission. The Falcon 9 continued into orbit and deployed its 60 Starlink payloads, and the booster was unable to land successfully.<\/p>\n

SpaceX has launched 111 Falcon 9 and Falcon Heavy rocket missions to date. All but one Falcon 9 flight had 10 Merlin engines (a special Falcon 9 configuration for a Dragon abort test did not have an upper stage engine), and the Falcon Heavy missions each had 28 engines, adding up to 1,163 Merlin engine flights in the Falcon 9 era, more than any other large U.S. rocket engine. Accounting for the three in-flight engine failures, the Merlin engine has amassed a 99.7% success record.<\/p>\n

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Nine Merlin 1D engines on the aft end of a SpaceX Falcon 9 first stage booster. Credit: SpaceX<\/figcaption><\/figure>\n

Reed said SpaceX is learning about life limits on Falcon 9 booster components as the company sets new records for first stage reuse on Starlink missions. SpaceX\u2019s life-leading booster has launched and landed eight times, and the company is expected to match that record with another Falcon 9 first stage on a Starlink launch this week.<\/p>\n

\u201cWe get to fly our higher count flight-proven vehicles to take the Starlink satellites to orbit,\u201d Reed said. \u201cThe anomaly we saw on this one particularly, it was a higher count vehicle, and some of the components were actually the highest count. They were life-leaders.\u201d<\/p>\n

SpaceX engineers can take lessons learned from Starlink launches and determine where to add more inspections during rocket refurbishment, and what components need to be replaced between Falcon 9 flights.<\/p>\n

\u201cHere\u2019s where we need more inspections, here are the kinds of components we need to replace, and here\u2019s where we can actually upgrade the system, the algorithms, on the vehicle to even further detect and control what the vehicle needs to do, and that\u2019s what we\u2019re doing as we move forward,\u201d he said.<\/p>\n

Hans Koenigsmann, a senior advisor and former vice president at SpaceX, said last week that he expects the company to continue flying Falcon 9 boosters for more than 10 flights, which was once SpaceX\u2019s limit on Falcon 9 reuse before rockets needed a major overhaul.<\/p>\n

\u201cI\u2019m pretty sure we will get to 10 flights soon, and then we will continue to look at the booster and make an assessment (whether) we can move forward with it,\u201d he said Feb. 23. \u201cMy personal opinion is that we will probably continue until we see more damage on the booster.\u201d<\/p>\n

Koenigsmann said SpaceX will look at data rather than specifying a certain number of flights for each booster.<\/p>\n

\u201cWe will inspect them regularly, at regular intervals\u201d he said. \u201cAnd the next time you check that the engine held up and see if there\u2019s any damage there. To me, it is an engineering problem. I don\u2019t think the number of 10 is a magic number.<\/p>\n

\u201cAlso, for example, we could start phasing in new components at some point in time and actually extend the life of the booster,\u201d Koenigsmann said.<\/p>\n

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A Falcon 9 rocket accelerates through the speed of sound on Feb. 15. Credit: Stephen Clark \/ Spaceflight Now]<\/figcaption><\/figure>\n

Steve Stich, NASA\u2019s commercial crew program manager, said Monday that the space agency is participating in SpaceX\u2019s investigation into the Feb. 15 engine failure.<\/p>\n

\u201cWe will follow on with SpaceX\u2019s investigation, and we\u2019ll look at that, and that will be something we\u2019ll bring to our program control board and make sure that we have separation from that, and understand that anomaly before we go fly (with astronauts),\u201d he said.<\/p>\n

SpaceX plans to launch a reused Crew Dragon capsule on a previously-flown Falcon 9 booster on the company\u2019s next launch of astronauts. NASA commander Shane Kimbrough, pilot Megan McArthur, Japanese astronaut Akihiko Hoshide, and European mission specialist Thomas Pesquet will ride the Crew Dragon \u201cEndeavour\u201d spaceship to the International Space Station in late April. It\u2019s the same capsule that flew with NASA astronauts Doug Hurley and Bob Behnken on a test flight to the space station last year.<\/p>\n

Kimbrough and his crewmates will launch on a Falcon 9 booster making its second flight after taking off and landing in November on the previous Crew Dragon mission. The upcoming mission, known as Crew-2, will be the first to fly on a previously-flown Falcon 9 first stage.<\/p>\n

\u201cOur team really follows all the Falcon 9 flights, and we learn from each one,\u201d Stich said. \u201cOne of the things I really like about what\u2019s happening, is SpaceX\u2019s Starlink flights are pretty far out there in terms of the number of times they\u2019ve flown a booster. We\u2019re about to embark on our first reuse here for a crew vehicle. So what we\u2019re doing is we\u2019re learning from each of those flights, and we\u2019re feeding that back into our certification for reuse.\u201d<\/p>\n

Kimbrough said his crew has been briefed every month on the status of the Crew Dragon and Falcon 9.<\/p>\n

\u201cWe\u2019re very confident that they\u2019re gonna figure out whatever\u2019s gone wrong,\u201d he said. \u201cIt\u2019s just been a few little things on a few of these rockets. They\u2019re launching almost once a week, so when you\u2019re launching that often everything is not going to go perfectly. There\u2019s nothing major or catastrophic that\u2019s happened. It\u2019s just a few things on the rocket that are going to get worked out before our flight.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

File photo of nine Merlin 1D engines firing on a Falcon 9 launch in 2018. Credit: SpaceX SpaceX has concluded fatigue on an engine cover caused one of the nine Merlin 1D first stage engines on the company\u2019s most recent launch to shut down early during ascent, leading to the loss of the booster during […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1764,1858,1852,524,291,235,1718,1445],"class_list":["post-11829","post","type-post","status-publish","format-standard","hentry","category-news","tag-akihiko-hoshide","tag-b1059","tag-benji-reed","tag-commercial-crew","tag-commercial-space","tag-crew-dragon","tag-crew-2","tag-endeavour"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11829"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=11829"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11829\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=11829"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=11829"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=11829"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}